Centralizer for drill steels



June 11, 1940. F R 2,204,352

CENTRA-LIZER FOR DRILL'STEELS Filed May 25, 1938 \wml n n INVEQTQZA m1" HIS ATTORNEY Patente'd June 11, 1940 UNITED STATES PATENT OFFICE cnmauzna roa mun. s'rnnns George H.'Fue hrer, Phillipsbnrg, N. 1., to Ingersoll-Rand Company, Jersey City, N. 3., a

? corporation of New Jersey I Application May 25,1938, Serial Nb. 209,895

4 Claim.

chiefly toithe natural clearances between the m. chuck mechanism of the rock drill and the drill steel and the inherent resiliency of the drill Unless the. overhangin portion .of the drill I steel is stabilized it will whip about its axis and, in many instances, start the drill hole at a point ofi-set fromthe axis of the rock drill. This, as will be readily appreciated, necessitates a readjustment of l the rock drill to bring it into alignment with the drill hole, otherwise the drill 20 steel will be placed under serious strains and excessive. localized wearwill ocur on the chuck parts. i r i It is accordingly an-object of the present in- I vention to. stabilize theoverhangi portion of 25 the drill steel and thereby assure the correct starting of a drill hole. I Other objects will be in part obvious and in part pointed out hereinafter. a

In the'drawing accompanying this specification and in which similar reference numerals refer to similar parts, Figure 1 Ba longitudinal side elevation of a rock drilling mechanism equippedwith a centralizerc'onstructedin accordance with the prac- '35 tice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 2-2, I "Figure, 3 is a transverse view taken through Figure 2 on the line 3-3, and 40 Figure 4 is a plan view, partly in section.

Referring more particularly to the drawing, 29 .and 2| designate the front ends Ipfa rock drill and a shell, respectively, and 22 a drill'ste'el, the

shank of which may extend into the front end 4 5 of the rock drill 29 to' receive the blows of a hammer piston (not shown). The opposite or free end of the drill steel 22 constitutes the outwith the practice of the invention and designated in its entirety by 25, isattached to the 'front end of the shell .-2l.\ It comprises a support 26 6 having a flange 21 which seats against and is clamped to the front end of the shell 2| by bolts 5 28.- In the opposite end of the support 26 are a pair of bolts 29' serving as pivots for guide arms 30 which maintain the drill steel 22 in alignment with the rock drill 20.

The bolts 29 are .inclined with respect to the longitudinalv axis of the support 26 and are arranged angularly with respect to each other. They lie in diiferenttransverse planes, although in close proximity to each other, and have longitudinally extending flattd surfaces 3| which engage each other to prevent rotary movement'of the bolts in the support.

The guide arms 36 are arranged on the portions of the bolts 29 extending above the support and are provided with hubs 32 having bores 33 through which the bolts 29 extend. The bores f 33 are of larger diameter than the bolts to re- 'ceive bushings 34 which serve as wearing members between the bolts and the hubs. Each bore 33 comprises an enlarged portion 35 and; a re- -duced portion 36. These portions define a shoulv der. or seat 31 for a spring 38'acting against a shoulder 39 of 'the bushingjl to press the hubs 32 against seating surfaces 49, on the support 26, encircling the bolts" 29. The spring 38 also forces the bushing 34 firmly against a guard or cover 4| and presses the cover against the head with nuts 44 which seat against the lower surfaces of the support 28 for holding the bolts 29 in position and for adjusting. the tension of the springs". a

In order to assure the correct location of th' guide arms, both in the guiding and non-guiding positions, the hubs 32 and theseating surfaces 45 46 are provided with portions adapted to interelockingly engage each other. Preferably these portions are in the form of ribs 46 Ion the ends of the hubs 32 and; grooves 46 in the surfaces 40 to accommodate the ribs. Any suitable number 50 on ribs 45 and grooves 46 may be provided to assure ample locking contact between the .guide arms and the support for preventing undue vibratory movement obtheguide arms.

Additional means are, however, provided to as.

sure the retention of the guide arms in the guiding position. To this end the opposed surfaces of the guide arms are provided with recesses 41 for the accommodation of a latch 48 which is mounted on a pivot 49 seated in the support 26. On the free end of the latch 48 is a hook 50 the latch is the guide arms.

The arm portions of tha guide arms 30 may be of any suitable design. In the present instance they are provided with reinforcing ribs 53 which extend from the hubs 32. to the free ends of the guide arms wherein are formed the recesses 54 through which the drill steel 22 extends.

In the operation of the device, whenever it is desired to start a drill hole the arms 30 are rocked to the guiding positions-in which the drill steel 22 lies in the recesses 54. In this position of the guide arms the ribs lie in the grooves 46 and .the latch 48 will be in engagement with the arms 30 for holding them stationary.

The arms remain in the guiding position during the ensuing drilling operation. and when the rock drill advances into contact with the cam 52 the latch will be depressed to move the hook out of engagement with the guide arms. Upon further forward, movement the rock drill will engage the guide arms and rock them out of its path and into a position in which the ribs 45 will lie in other grooves 46 where the guidearms will be securely held by the springs 38 until again returned to the guiding position by the operator.

I claim:

1. A centralizer for drill steels, comprising a support, a pair of guide arms, pivots on the support for the guide arms, portions on the guide arms and the support interlockingly engaging each other in the guiding and non-guiding positions of the guide arms, and springs encircling the pivots acting on the guide arms and the pivots to maintain said portions in interlocking engagement.

2. A centralizer for drill steels, comprising a support. a pair of guide arms, pivots on the support for the guide arms. portions on the guide arms and thesupport interlockingly engaging each other 'in the guiding and non-guiding positions of the guide arms, springs encircling the pivots acting on the guide arms and the pivots to maintain said portions in interlocking engagement, a latch on the support to engage the guide arms for locking said guide arms in guiding position, and a spring to press the latch means into and hold it in engagement with the guide arms.

3. A centralizer for drill steels, comprising a support, a pair of guide arms, pivots in the support for the guide arms arranged angularly with respect to each other, latch 'means on the sup port movable into and out of engagement with the guide arms to retainthe guide arms in guiding position and to release the guide arms, and a spring to press the latch means into and hold it in engagement with the guide arms.

4. In a centralizer for drill steels, the combination of a guide shell and a rock drill slidable thereon, a support on the shell; a pair of guide arms. pivots on the support for the guide arms, a latch on the support to engage the guide arms for locking said guide arms in guiding position and having a portion for engagement with the rock drill whereby the latch is disengaged from the guide arms when the rock drill approaches said guide arms.

GEORGE H. FUEHRER. 

